For some time, as a method or device for controlling the arrangement of a vehicle group, there has been known a method or device for acquiring braking distances of the other vehicles via vehicle-to-vehicle communication within the vehicle group and disposing a vehicle having a longer braking distance to a position closer to the head of the vehicle group (for example, refer to Patent Literature 1).    [Patent Literature 1] Japanese Unexamined Patent Application Publication No. H10-293899